US2023393300A1PendingUtilityA1
Multi-sector data correction method and system for gamma imaging while drilling
Assignee: CHINA PETROLEUM & CHEM CORPPriority: Oct 16, 2020Filed: Oct 15, 2021Published: Dec 7, 2023
Est. expiryOct 16, 2040(~14.3 yrs left)· nominal 20-yr term from priority
Inventors:Luyang DingNingning YangHaiquan TangZhen YangNan LinMingquan HuangQinglong LiuQuanjin YangXiaolin ZhangZhiyong ZhangChuntian HanHai MaXiaohui CuiChao-Wen LuXin Cheng
G01V 5/12G06F 17/16E21B 47/12E21B 7/04E21B 47/022G06F 17/18E21B 47/0025E21B 47/026E21B 41/00E21B 2200/20
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Claims
Abstract
A multi-sector data correction method for gamma imaging while drilling includes the steps of: (a) dividing each gamma imaging sector into a plurality of counting zones; (b) counting a number of valid counting pulses for each counting zone at a predetermined time interval during MWD; (c) constructing a plurality of measurement vectors based on a value of recording times of each counting zone; (d) establishing a correction matrix with a conditional number less than a set value through an optimization algorithm; and (e) calculating a gamma intensity of each measured sector with the plurality of measurement vectors and the correction matrix as constructed, so as to complete the correction on the measurement data of each measured sector for each predetermined time interval. This method eliminate problems such as rotational measurement distortion of the gamma imaging while drilling tool and improve the accuracy of calculating the formation dip angle.
Claims
exact text as granted — not AI-modified1 . A multi-sector data correction method for gamma imaging while drilling,
characterized in that the method comprises steps of: (a) dividing each gamma imaging sector into a plurality of counting zones; (b) counting a number of valid counting pulses for each counting zone at a predetermined time interval during measurement while drilling; (c) constructing a plurality of measurement vectors featuring measurement results of all sectors based on a value of recording times of each counting zone; (d) establishing a correction matrix with a conditional number less than a set value, said correction matrix being used to correct measurement data; and (e) calculating a gamma intensity of each measured sector with the plurality of measurement vectors and the correction matrix as constructed, so as to complete the correction on the measurement data of each measured sector for each predetermined time interval.
2 . The multi-sector data correction method for gamma imaging while drilling according to claim 1 , characterized in that in said Step (c), all the counting zones are divided into a plurality of groups, and the value of recording times of each counting zone in each group is used to construct a corresponding measurement vector,
wherein a number of groups into which the counting zones are divided is equal to a number of the counting zones formed by equally dividing each sector, and each group of counting zones is composed of the counting zones that are discontinuously extracted from each sector, any adjacent counting zones in a same sector not being in a same group.
3 . The multi-sector data correction method for gamma imaging while drilling according to claim 1 , characterized in that in said Step (e), the gamma intensity G of each measured sector is calculated with an expression as follows:
G=γ −1 ·( M 1 +M 2 + . . . +M n )
wherein M n denotes the n th measurement vector, γ is the correction matrix, γ=γ 1 +γ 2 + . . . +γ n , and γ n denotes the n th optimization matrix.
4 . The multi-sector data correction method for gamma imaging while drilling according to claim 3 , characterized in that
in said Step (c), all the counting zones are divided into two groups, and a first measurement vector and a second measurement vector are constructed respectively with the value of recording times per unit time for each counting zone in each group, wherein each group of the counting zones is formed by discontinuously extracting the counting zones from consecutive counting zones arranged along a circumferential direction, any adjacent counting zones not being in the same group; wherein said first measurement vector is a one-dimensional vector, each vector unit of which is a value of recording times per unit time for each counting zone in a first group of counting zones, these values being arranged in a sequence corresponding to the counting zones in the circumferential direction; and said second measurement vector is a one-dimensional vector, each vector unit of which is a value of recording times per unit time for each counting zone in a second group of counting zones, these values being arranged in a same way as those of the first measurement vector and with a same starting point.
5 . The multi-sector data correction method for gamma imaging while drilling according to claim 4 , characterized in that the step of constructing said correction matrix comprises:
determining a number of units within the correction matrix based on a number of groups of all counting zones; setting an adjustment coefficient and multiple correction coefficients, wherein a number of correction coefficients is equal to a sum of a number of elements of the first measurement vector and that of the second measurement vector; establishing, based on the adjustment coefficient and multiple correction coefficients, a correction unit matrix for each measurement vector, thereby forming the correction matrix; and determining, based on the vector composed of said multiple correction coefficients as an independent variable, an optimal independent variable for which the conditional number of the correction matrix reaches or approaches a global minimum through an optimization algorithm, thereby obtaining an optimal correction matrix with the optimal independent variable.
6 . The multi-sector data correction method for gamma imaging while drilling according to claim 5 , characterized in that in said Step (d), a correction matrix γ with a conditional number less than 10 is constructed with an expression as follows:
γ=γ 1 +γ 2
wherein γ 1 is expressed as follows:
γ
1
=
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1
φ
1
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3
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7
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7
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and γ 2 is expressed as follows:
γ
2
=
[
φ
2
a
·
φ
2
0
0
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0
φ
4
a
·
φ
4
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6
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n
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]
wherein n denotes a number of sectors to be measured, a denotes the adjustment coefficient, and [φ 1 , φ 2 , φ 3 , . . . , φ 2n ] denotes the vector of correction coefficients.
7 . The multi-sector data correction method for gamma imaging while drilling according to claim 6 , characterized in that in said Step (e), the gamma intensity G of each measured sector is calculated with an expression as follows:
G=γ −1 ·( M 1 +M 2 )
wherein M 1 and M 2 denote the first and second measurement vectors, respectively, and γ denotes the correction matrix after optimization.
8 . A multi-sector data correction system for gamma imaging while drilling, characterized in that the system comprises:
a counting-zone dividing module, configured to divide each gamma imaging sector into a plurality of counting zones; a pulse recording module, configured to count a number of valid counting pulses for each counting zone at a predetermined time interval during measurement while drilling; a measurement-vector constructing module, configured to construct a plurality of measurement vectors featuring measurement results of all sectors based on a value of recording times of each counting zone; a correction-matrix establishing module, configured to establish a correction matrix with a conditional number less than a set value through an optimization algorithm, said correction matrix being used to correct measurement data; and a gamma-intensity calculating module, configured to calculate a gamma intensity of each measured sector with the plurality of measurement vectors and the correction matrix as constructed, so as to complete the correction on the measurement data of the measured sector for each predetermined time interval.
9 . The multi-sector data correction system for gamma imaging while drilling according to claim 8 , characterized in that the measurement-vector constructing module is configured to divide all the counting zones into a plurality of groups, and construct a corresponding measurement vector with the value of recording times of each counting zone in each group,
wherein a number of groups into which the counting zones are divided is equal to a number of the counting zones formed by equally dividing each sector, and each group of counting zones is composed of the counting zones that are discontinuously extracted from each sector, any adjacent counting zones in a same sector not being in a same group.
10 . The multi-sector data correction system for gamma imaging while drilling according to claim 8 , characterized in that the gamma-intensity calculating module is configured to calculate the gamma intensity G of each measured sector with an expression as follows:
G=γ −1 ·( M 1 +M 2 + . . . +M n )
wherein M n denotes the n th measurement vector, γ is the correction matrix, γ=γ 1 +γ 2 + . . . +γ n , and γ n denotes the n th optimization matrix.
11 . The multi-sector data correction system for gamma imaging while drilling according to claim 10 , characterized in that
the measurement-vector constructing module is configured to divide all the counting zones into two groups, and construct a first measurement vector and a second measurement vector respectively with the value of recording times per unit time for each counting zone in each group, wherein each group of the counting zones is formed by discontinuously extracting the counting zones from consecutive counting zones arranged along a circumferential direction, any adjacent counting zones not being in the same group; wherein said first measurement vector is a one-dimensional vector, each vector unit of which is a value of recording times per unit time for each counting zone in a first group of counting zones, these values being arranged in a sequence corresponding to the counting zones in the circumferential direction; and said second measurement vector is a one-dimensional vector, each vector unit of which is a value of recording times per unit time for each counting zone in a second group of counting zones, these values being arranged in a same way as those of the first measurement vector and with a same starting point.
12 . The multi-sector data correction system for gamma imaging while drilling according to claim 11 , characterized in that the correction-matrix establishing module is configured to:
determine a number of units within the correction matrix based on a number of groups of all counting zones; set an adjustment coefficient and multiple correction coefficients; establish, based on the adjustment coefficient and multiple correction coefficients, a correction unit matrix for each measurement vector, thereby forming the correction matrix; and determine, based on the vector composed of said multiple correction coefficients as an independent variable, an optimal independent variable for which the conditional number of the correction matrix reaches or approaches a global minimum through an optimization algorithm, thereby obtaining an optimal correction matrix with the optimal independent variable, wherein a number of correction coefficients is equal to a sum of a number of elements of the first measurement vector and that of the second measurement vector.
13 . The multi-sector data correction system for gamma imaging while drilling according to claim 12 , characterized in that the correction-matrix establishing module is configured to establish a correction matrix γ with a conditional number less than 10 with an expression as follows:
γ=γ 1 +γ 2
wherein γ 1 is expressed as follows:
γ
1
=
[
a
·
φ
1
φ
1
0
0
…
0
0
a
·
φ
3
φ
3
0
…
0
0
0
a
·
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5
φ
5
0
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0
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0
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7
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φ
2
n
-
1
0
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…
a
·
φ
2
n
-
1
]
and γ 2 is expressed as follows:
γ
2
=
[
φ
2
a
·
φ
2
0
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0
0
φ
4
a
·
φ
4
0
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6
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8
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8
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0
0
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a
·
φ
2
n
0
0
0
…
φ
2
n
]
wherein n denotes a number of sectors to be measured, a denotes the adjustment coefficient, and [φ 1 , φ 2 , φ 3 , . . . , φ 2n ] denotes the vector of correction coefficients.
14 . The multi-sector data correction system for gamma imaging while drilling according to claim 13 , characterized in that the gamma-intensity calculating module is configured to calculate the gamma intensity G of each measured sector with an expression as follows:
G=γ −1 ·( M 1 +M 2 )
wherein M 1 and M 2 denote the first and second measurement vectors, respectively, and γ denotes the correction matrix.
15 . A computer apparatus, comprising a processor and a memory, said memory being stored thereon at least one instruction, at least one program, a set of codes or a set of instructions, wherein said at least one instruction, at least one program, said set of codes or said set of instructions is loaded and executed by said processor to perform the multi-sector data correction method for gamma imaging while drilling according to claim 1 .
16 . A computer readable storage medium, stored thereon at least one instruction, at least one program, a set of codes or a set of instructions, wherein said at least one instruction, at least one program, said set of codes or said set of instructions is loaded and executed by said processor to perform the multi-sector data correction method for gamma imaging while drilling according to claim 1 .Cited by (0)
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